Topic: Crazy vibration and grind on coast

[JAWS85]

So here is what I have 1988 std cab, 5 spd dual case 10deg. front range mount. Just rebuild and balanced rear shaft.
Problem...... 50mph plus 4th and 5th gear if I let off the throttle (not under a positive load) I get the noise.
Or just put it neutral and coast,  I get it. If I down shift to slow down Iam okay.
Goes into gear fine, just build the truck, and cases. Also clean fluid 80/90 in everything..... and no metal on magnets.
I read somewhere on here that a double joint drive shaft may solve this issu? Ideas?   

[OOPS]

Do you have your driveshaft angles set right?

http://www.4crawler.com/4x4/CheapTricks/Driveline-101.shtml

[JAWS85 [OP]]

Thanks for the good information and the link. I installed my new drive shaft and have no issues yet.
Measure twice cut once.

[grant426]

I had same issue, turns out the drive shaft was bent. Almost 3/8 of an inch.